The objective of this project is the research and development of suitable analytical methods to: (1) establish the structure and purity of potential anti-AIDS agents and new antiviral drugs, (2) determine physical, chemical and biochemical properties, including octanol-water partition coefficients , of these compounds and their metabolites, and (3) measure these drugs and their metabolites in biological samples to elucidate pharmacology and to determine pharmacokinetics. High-performance liquid chromatography and mass spectrometry are emphasized techniques. Compounds of current interest are dideoxynucleosides including ddG, 6-halo-dd-Purines. 2-NH(2)-6-halo-dd-Purines, 2'-F-dd-ara-A, 2'-F-dd-ara-I, 2'-F-dd-ara-G,2'-F-dd-C, 2'-F-dd-ara-C and 6-substituted-2'-F-dd-Purines.